Engine cooling system

Abstract

An internal combustion engine having a cooling system which cools a portion of a fuel delivery system is disclosed. The engine has at least one combustion chamber and an intake system for supplying air to the combustion chamber. The fuel delivery system includes a fuel supply mechanism for supplying fuel under pressure to a fuel injector through a fuel rail, the fuel injector supplying fuel to the combustion chamber. The cooling system includes a coolant supply mechanism for supplying coolant to a cooling jacket about at least a portion of the fuel rail for cooling fuel passing through the fuel rail.

What is claimed is: 
     
       1. An outboard motor comprised of a power head containing an internal combustion engine and a protective cowling enclosing said engine, a driveshaft housing and lower unit depending from said power head and containing a propulsion device driven by said engine, said engine having at least one combustion chamber, an intake system for supplying air to said combustion chamber, a fuel delivery system for supplying fuel to said combustion chamber, said fuel delivery system including a fuel supply mechanism for supplying fuel under pressure to a fuel injector through a fuel conduit, said fuel injector supplying fuel to said combustion chamber, and a cooling system for said engine, said cooling system including a cooling jacket for said engine and a cooling jacket for said fuel supply system, a coolant supply mechanism for drawing water from a body of water in which said outboard motor is operating and supplying water to said engine cooling jacket, a thermostat for sensing the temperature of water in said engine cooling jacket and returning water to the body of water when the temperature in said engine cooling jacket is above a predetermined value, and for supplying a portion of the returned water through said fuel supply system cooling jacket only when said water is above said predetermined temperature. 
     
     
       2. The outboard motor in accordance with claim 1, wherein said cooling system includes a pump in said driveshaft housing and lower unit driven by said engine for delivering the water to the cooling system. 
     
     
       3. The outboard motor in accordance with claim 1, wherein said fuel conduit cooling jacket comprises a cooling jacket surrounding a fuel rail that supplies fuel to the fuel injector. 
     
     
       4. The outboard motor in accordance with claim 3, wherein said fuel rail extends along said engine from a first end to a second end with fuel injectors spaced therealong. 
     
     
       5. The outboard motor in accordance with claim 4, wherein said fuel injectors are electronically operated. 
     
     
       6. The outboard motor in accordance with claim 5, wherein a fuel line extends from said injectors to a pressure regulator and a return line extends from said pressure regulator back to said fuel supply mechanism. 
     
     
       7. The outboard motor in accordance with claim 6, wherein said fuel supply mechanism comprises a pump delivering fuel from a vapor separator. 
     
     
       8. The outboard motor in accordance with claim 1, wherein said fuel conduit comprises a fuel rail in the form of a pipe having an outer wall and said fuel supply system cooling jacket comprises a conduit positioned around said pipe and cooperating therewith to define a space therebetween through which water flows. 
     
     
       9. The outboard motor in accordance with claim 1, wherein said fuel injector directs fuel into said combustion chamber along an intake passage leading to said combustion chamber.